Abstract: A dialysis machine valve manifold assembly includes a plurality of pneumatic valves; a plate including a first side and a second side, the plurality of pneumatic valves mounted to the first side of the plate, the second side of the plate defining a plurality of pneumatic flow paths; and a port header mounted removably to the plate, the port header including a plurality of ports configured to connect sealingly to pneumatic tubing, the ports in fluid communication with the pneumatic valves via the pneumatic flow paths defined in the plate.

Abstract: The present invention aims to appropriately cool an operation unit and to suppress power consumption and noise according to the configuration and the operation state in a computer system of an enclosure. A plurality of system cooling fans for cooling the operation unit of the computer system installed in the enclosure and an enclosure management module for controlling the rotation of each system cooling fan are arranged, where the enclosure management module stores in advance the supply cooling amount which is to be supplied to the operation unit by each system cooling fan, acquires information related to a temperature of the operation unit and calculates a necessary cooling amount which is to be required in the operation unit based on the information, and determines the rotation number of each system cooling fan based on the supply cooling amount and the necessary cooling amount.

Abstract: Systems and methods for monitoring operation of a pump, including verifying operation or actions of a pump, are disclosed. A baseline profile for one or more parameters of a pump may be established. An operating profile may then be created by recording one or more values for the same set of parameters during subsequent operation of the pump. The values of the baseline profile and the operating profile may then be compared at one or more points or sets of points. If the operating profile differs from the baseline profile by more than a certain tolerance an alarm may be sent or another action taken, for example the pumping system may shut down, etc.

Abstract: A compressor system is disclosed, comprising a first pump driven by a D/C motor, a second pump driven by an A/C motor, and a switch which allows a user to manually selectively engage of one of the D/C motor or NC motor, including a gauge having a user settable shut-off mechanism which interrupts power to at least one of D/C or A/C motors. Also disclosed is a gauge configured to display system pressure independent of the user settable shut-off mechanism. A gauge having a rotatable bezel with a needle stop comprising a first needle rotatably coupled to a gauge shaft, and a second needle fixable coupled to the gauge shaft, and a spring disposed between the first and second needles, the spring configured to bias the first needle into the second needle so changes in pressure causes rotation of both is also disclosed.

Abstract: A multipurpose hemofiltration system and method are disclosed for the removal of fluid and/or soluble waste from the blood of a patient. The system continuously monitors the flow rates of drained fluid, blood, and infusate. When necessary, the pumping rates of the infusate, drained fluid and blood are adjusted to remove a preselected amount of fluid from the blood in a preselected time period. A supervisory controller can monitor patient parameters, such as heart rate and blood pressure, and adjust the pumping rates accordingly. The supervisory controller uses fuzzy logic to make expert decisions, based upon a set of supervisory rules, to control each pumping rate to achieve a desired flow rate and to respond to fault conditions. An adaptive controller corrects temporal variations in the flow rate based upon an adaptive law and a control law.

Abstract: Embodiments of the present invention are related to a pumping system that accurately dispenses fluid using a multiple stage (“multi-stage”) pump. More particularly, embodiments of the present invention provide for control of a feed stage pump to regulate fluid pressure at a downstream dispense stage pump. According to one embodiment of the present invention, a pressure sensor at the dispense stage pump determines the pressure in a dispense chamber. When the pressure reaches a predefined threshold, the dispense stage pump can begin to increase the available volume of the dispense chamber, thereby causing the pressure in the dispense chamber to drop. As the pressure decreases/increases at the downstream pump, the pressure applied by the upstream pump can bed increased/decreased.

Abstract: A fan controlling apparatus for controlling a plurality of fans which are tandemly arranged in ventilation direction of a chamber to control a temperature of a hot generating object placed in the chamber, the apparatus includes a memory for storing data of the rotational speed each of fans in relation to the temperature of the heat generating object, and a controller for controlling the rotational speed of each of the fans respectively in dependence on the temperature of the heat generating object in reference to the data stored in the memory.

Abstract: A water pump with a housing that has a pump housing part provided with an intake opening and an outlet opening and a motor housing part. An impeller with a shaft is rotatably arranged in the pump housing part. An electric motor is received in the motor housing part. The electric motor is an electronically commutated motor with a rotor and coils. In the housing, control and governing electronics for the electric motor are arranged that have a speed detection, a processor, and a data storage device. The electronics are arranged in the motor housing part and potted therein in a water-tight way. An integrated BUS control module is provided. The control electronics and the governing electronics can be arranged separate from one another on different circuit boards.

Abstract: An air compressor 20, for enabling to restart a fan motor when an inverter trip generates within an inverter control of the fan motor, as well as, to continue supplying of compressed air therefrom, comprises: a compressor main body 1; a compressor motor 2 for driving this compressor main body 1; a fan motor 9b for driving a fan 9a; an inverter for controlling the fan motor; and a controller 10 for controlling driving of the compressor motor 2 and driving of the fan motor 9b. The controller 10 conducts such control that the fan motor 9b is brought into a restart waiting condition while continuing operation of the compressor motor 2 when an inverter trip generates, and thereafter to restart the fan motor 9b.

Abstract: A capacity control algorithm for a multiple compressor liquid chiller system is provided wherein the speed and number of compressors in operation are controlled in order to obtain a leaving liquid temperature setpoint. In response to an increase in the load in the chiller system, the algorithm determines if a compressor should be started and adjusts the operating speed of all operating compressors when an additional compressor is started. In response to a decrease in the load in the chiller system with multiple compressors operating, the algorithm determines if a compressor should be de-energized and adjusts the operating speed of all remaining operating compressors when a compressor is de-energized.

Abstract: A method and apparatus for reducing the pressure in an enclosure are provided. The method includes at least one primary pump on the outlet side and one secondary pump on the inlet side connected in series in the flow path of the pumped gases and driven in the same rotation direction by a first electric motor and a second electric motor, respectively, controlled by an electronic control module for modifying the speeds of the two electric motors independently, and includes at least one step, during reducing the pressure in the enclosure, of progressively increasing the rotation speed of the secondary pump in accordance with a rotation speed variation law of the secondary pump and at the same time progressively reducing the rotation speed of the primary pump in accordance with a rotation speed variation law of the primary pump.

Abstract: A method for analysis of solvent evaporation patterns includes: continuously evacuating the gas of a single-component or multicomponent solvent evaporated under desired evaporation conditions from an object containing the single-component or multicomponent solvent housed in an airtight container, with evacuation means from the airtight container to an exhaust path connected to an exhaust port of the evacuation means; sampling a gas at predetermined time intervals from a desired point between the airtight container and the outlet of the exhaust path with the continuous evacuation maintained; measuring the solvent gas contained in the sampled gas; and determining an evaporation pattern of the solvent from the object under the desired evaporation conditions, from results of the measurement.

Abstract: A compressor system includes a lead compressor operable to produce a flow of compressed fluid at a first output and a lag compressor operable to produce a flow of compressed fluid at a second output. The sum of the first output and the second output defines a system output. A lead variable speed motor is operable to drive the lead compressor at a first compressor speed to vary the first output and a lag variable speed motor is operable to drive the lag compressor at a second compressor speed to vary the second output. A sensor is operable to measure a system load, and a lead motor drive is operable to control the speed of the lead variable speed motor and to set a desired operating state of the lag variable speed motor in response to a comparison of the system load and the system output.

Abstract: A modular system for the control of at least one compression system for the compression a fluid medium, said compression system comprising compressors (C1-C7) and their controllers (A1-A7) for the compression of the fluid medium, secondary treatment devices for the treatment of the medium delivered from the compressors, and piping systems (17-19, 23) for conducting the fluid medium to a place of consumption (16, 22), said control system comprising a control unit (3) containing a data processing system (34) for controlling the compression system, a user interface (35) including a display associated with it and transmission means for the transmission of control data between the control unit, the controllers and pressure sensors. The transmission means consist of data communication buses, preferably serial communication buses (30-32) and a data communication port unit (33) serving to connect the bus to the control unit (34). The controllers and pressure sensors are connected to common data communication buses.

Abstract: The present invention relates to a piston pump for generating a delivery flow, which is substantially free of pulsation, in particular to a dual piston pump, and to a method for controlling such a piston pump delivering a pumped medium from a low-pressure area into a high-pressure area, wherein measuring sensors detecting mechanical forces or moments transmitted by the structure of the pump or its associated drive unit are used instead of the pressure or flow sensors usually employed for this purpose.

Abstract: An integrated welder, generator and hydraulic unit that includes a housing that at least partially contains components of a welder, generator and a hydraulic pump. An engine, an electric current generator, and a hydraulic pump are at least partially mounted in the housing. The electric current generator is at least partially connected to the engine to be at least partially driven thereby. The hydraulic pump can be at least partially powered by the electric current generator or the fuel powered engine during the operation of the engine. The integrated welder, generator and hydraulic unit can also include an air compressor.

Abstract: A gradient pump apparatus which is capable of continuously and precisely feeding, to a chromatograph, eluents at intervals of certain time and at a constant flow rate in units of nano-liter per minute while the composition of two or more eluent components is changed. The gradient pump apparatus includes a 10-port valve for switching an eluent mixing pipe, in which a feed pressure of eluents changes with time, to be connected to a first loop which is supplied with another eluent from an isocratic pump that should function to hold an eluent feed pressure constant, and which is connected to an analytic section, or to a second loop through which the eluents are drained. A controller computes a difference between a value of the pressure in the eluent mixing pipe and a value of the eluent feed pressure applied from the isocratic pump when the eluent mixing pipe is connected to the second loop.

Abstract: The apparatus of the present invention provides a compact dual-pump assembly for an automotive transmission. The dual-pump assembly preferably includes a housing having a valve assembly mounted thereto. The valve assembly includes a shuttle valve disposed in fluid communication with a pressure regulating valve. An on-axis pump is mounted to the housing in fluid communication with the shuttle valve and the pressure regulating valve. An off-axis pump in fluid communication with the shuttle valve is mounted to the housing in close proximity to the on-axis pump such that the dual-pump assembly is compact.

Abstract: One embodiment of the present invention provides a system that determines fan speeds for a set of fans in a computer system. During operation, the system receives time-series data collected by a vibration transducer associated with the computer system, wherein the vibration transducer is configured to record mechanical vibrations from the set of fans. Next, the system performs a spectral analysis on the time-series data to obtain frequency peaks associated with fan speeds for individual fans in the set of fans. The system then identifies fan speeds for the individual fans in the set of fans from the frequency peaks.

Abstract: A fan filter unit includes a plurality of fan motors, a plurality of detectors, a total controller, and a filter. Each of the fan motors includes a fan and a motor. The total controller performs a feedback control to the respective fan motors so that the detected rotating speeds are identical with a set rotating speed, based on rotating speeds detected by the detectors. When one detected rotating speed value by any of the detectors is smaller than the other detected rotating speed value by the other detector, the total controller performs a tuning control of rotating speed so that a rotating speed of the other fan motor is adjusted to the slower rotating speed of the fan motor.

Abstract: The invention relates to a method for controlling the oil supply device of an automatic planetary transmission, comprising a main oil pump (HP), which is mechanically drivably connected to the drive shaft of an internal combustion engine (VM), and an auxiliary oil pump (ZP) that may be driven via a controllable electric motor, the automatic transmission (ATG) being part of a parallel hybrid powertrain of a motor vehicle having an input shaft (5), which may be connected via a separating clutch (K) to the drive shaft (2) of the internal combustion engine (VM) and is permanently drivably connected to the rotor (4) of an electric machine (EM).

Abstract: The present invention refers to a control equipment for a pressure set, said pressure set being made up of a main pump and at least one auxiliary pump, characterised in that it comprises a housing fitted to the exit of the main pump, therewithin it is provided with: a pressure transducer; a minimum flow detector associated to the circulation pipe that is related to the main pump; a frequency changer to regulate the flow speed that is flowing through the hydraulic pipe that is connected to the main pump; and an electronic control circuit electrically connected to the pressure transducer, the flow detector, so that based on the signals received from them it sends a signal to the frequency changer so as to regulate the working parameters of the main pump and at least one auxiliary pump, keeping the pressure value unchanged throughout the workings of the pressure set.

Abstract: The invention concerns an installation for high pressure compression with several stages, normally used for producing PET bottles. The inventive installation comprises a main pipe (2) emerging in a baffle plate (3), wherein at least two compressors (4, 5) are mounted in series each having its own drive member (9, 10). The installation is equipped with means (7) for determining the pressure at the output of the main pipe (2), said installation being connected to a control box (8). Typically, the control box (8) is connected to at least two of the drive members (9, 10) of the compressors (4, 5) and ensures monitoring of said compressors such that the latter rotate jointly whether charged or uncharged. Thus, the compressors (4, 5) are jointly charged based on the pressure prevailing in the baffle plate (3), such that the charging of the compressor representing the overpressure stage, the compressor(s) of the lower compression stages are automatically and jointly charged.

Abstract: The present invention provides a new and unique method and apparatus for operating and running multiple pumps in a system together at a substantially synchronous torque to achieve a desired setpoint. Each of the multiple pumps may be operated with a variable speed drive. The present invention may also take the form of the system having the multiple pumps with a system controller for operating and running the multiple pumps, a pump for operating and running in such a system, a system control module for such a system controller, as well as a pump control module for running and operating such a pump.

Abstract: While one of ventilation fans operates, the other ventilation fan is at rest. Air flows from the operating ventilation fan to the ventilation fan at rest. The airflow passes through an air passage defined in a heat radiating member located between the ventilation fans. Dust cumulates at the entrance of the air passage. The other ventilation fan is then driven to operate while the operating ventilation fan is brought to rest. Airflow is generated in the reverse direction. The airflow is inverted within the air passage. The inverted airflow serves to remove the dust from the entrance of the air passage. The cumulation of the dust can thus reliably be avoided. Accordingly, no dust filter is required in the path of airflow outside the air passage. Airflow of a sufficient amount can always be maintained in the air passage.

Abstract: A pump control system includes a plurality of different variable speed pumps. Each of the pumps can be operated at a different speed to equalize pump loads. A system wide proportional integral differential control loop increases and decreases the speed of all pump motors to maintain a desired system output pressure. A second proportional integral differential control loop associated with each pump adjusts pump speed to equalize a load profile for each respective pump.

Abstract: An apparatus includes a pump; a gas pressure sensor; a microfluidic chip defining a microfluidic conduit; and a gas conduit providing fluid communication between the pump, the gas sensor and the microfluidic conduit; and a controller coupled to the pump and the gas pressure sensor, whereby the controller controls the pump, thereby controlling the gas pressure at the microfluidic conduit. An apparatus includes a microfluidic chip defining a microfluidic conduit extending from a microfluidic source electrode to a microfluidic ground electrode; a first resistor coupled to the microfluidic source electrode; a first and a second voltage divider, the first divider coupling a first power ground to a side of the first resistor opposite the microfluidic chip, the second divider coupling a second power ground to the lead between the first resistor and the microfluidic source electrode, and a first voltage sensor; and a second voltage sensor. Also included are methods of operating the apparatus.

Abstract: A method for optimizing the operation of several compressor units in a natural gas compression station. After a second or further compressor unit is started, the speeds of the running compressor units are set according to a fixed speed ratio in relation to characteristic data established for each compressor unit. The fixed speed ratio is altered by adjusting the rate of flow to the same percentage via the speed of rotation until the preventive pump valves of the gas compressor station are closed, whereupon the operating points of the compressor units are guided, where possible, in the characteristic data thereof, to the maximum efficiency. The optimum set speed values are determined according to continuous operating characteristics of the gas compression station by coordinated variation of the set speeds of the compressors, taking into account fuel consumption of the gas compression station. The stored fixed speed ratio is adjusted according to the optimum set speed values thus determined and stored.

Abstract: The invention aims at reducing the beating noise generated from motors of equipments placed in a galley unit of an aircraft. A galley unit 1 of an aircraft includes a cabinet 10 formed of honeycomb panels and the like. The cabinet 10 has a counter 50 for cooking, and a compartment 20 formed under the counter 50 for storing service carts 30. A plurality of ovens 100 for heating warm dishes are provided above the counter 50. Each oven 100 has a fan motor for making the inner heat even. If all the fan motors of the ovens are driven at the same rotation frequency, a beating noise will be generated from the motor and amplified through the compartment 20. Therefore, the rotation frequencies of the fan motors are slightly varied.

Abstract: In order to provide a compressed air manufacturing facility which can increase a stability of a supply pressure while obtaining an energy saving effect, in a compressed air manufacturing facility provided with a compressor compressing an air, an electric motor driving the compressor, and an inverter variably controlling a rotating speed of the electric motor, the compressed air manufacturing facility is provided with a pressure sensor detecting a discharge pressure of the compressor at an upstream side position of a discharge air system connected to a discharge side of the compressor, and a control apparatus computing a pressure loss of the discharge air system in correspondence to a rotating speed of the electric motor, and changing a control range of the discharge pressure of the compressor at the upstream side position of the discharge air system on the basis of the computation in such a manner that a terminal pressure at a downstream side position of the discharge air system comes to a predetermined range

Abstract: A vacuum pump (10) includes a pump unit (14) and an operating unit (12) arranged spaced from the pump unit (14). The operating unit (12) is connected with the pump unit (14) for controlling it. The pump unit (14) and the operating unit (12) respectively comprise a transceiver module (20,22) for transmitting and receiving control and operational data bidirectionally in a wireless manner. The pump unit (14) and the operating unit (12) are exclusively connected with each other in a wireless manner. By the omission of electrical lines, the induction of interfering signals is excluded. Wall perforations for lead-through of electrical lines are omitted.

Abstract: In accordance with some embodiments, a pumping station controller (14) is provided for monitoring pumping station hardware such as a well level sensor (8) and pumps (10a, . . . , 10n). A user interface (12) enables a user to input data to the controller (14) for controlling the operation of the pumps (10) based on the sensed liquid level. Pumping hardware configurations vary from site to site so that wiring the hardware to the controller may be confusing for the user. To address this problem the controller may comprise a software product (20). The software product may comprise instructions for processor (19) to determine a suitable wiring configuration between the controller (14) and the pumping station hardware, based upon user entered parameters identifying the pumping station hardware to be used.

Abstract: One aspect of the present invention provides a multi-channel controller that can control a plurality of fuel pump devices, with each fuel pump device having its own dedicated communications channel. Accordingly, aspects of the present invention enable existing wiring and fuel pump devices to be preserved while turning an existing fuel pump device installation into a network of may point-to-point networks.

Abstract: A radiation fan driving apparatus aims to allow a non-stop power supply system to output electric power to drive a radiation fan to continuously rotate at a lower speed to perform heat dissipation even the power supply device is electrically connected to an external electric power source. A control circuit and isolation protective elements are provided so that when the main power source of a computer host is ON, the power supply device delivers electric power through the main power system or the control circuit to the radiation fan to rotate at high speed to provide optimal heat dissipation effect.

Abstract: A multi-stage gas compressing apparatus comprises a primary gas compressor and a secondary gas compressor. A gas compressed in the primary gas compressor is transferred to the secondary gas compressor in which the gas is further compressed. A detector detects upper and lower limits of discharge pressure from the secondary gas compressor, and a signal is sent from the detector to a control device connected to the primary and secondary gas compressors. Then, the primary and secondary gas compressors are started or stopped by the control device.

Abstract: A cooling fan module for a motor vehicle has a first fan motor which is used to drive a first cooling fan and a second fan motor which is used to drive a second cooling fan. A control unit (6, 13) is associated with the first fan motor (2, 11), which operates the first fan motor (2, 11) and the second fan motor (4, 12, 23) simultaneously, in order to provide an economical and compact technical solution for the cooling fan.

Abstract: A system for controlling air flow comprises an inlet, a first compressor, a first pressure sensor, a second pressure sensor, a first temperature sensor, and a first controller. The inlet is configured to direct a first stream of air into the system. The first compressor is configured to pull in the first stream of air through the inlet and compress the first stream of air. The first pressure sensor senses a first pressure of the first stream of air prior to compression in the first compressor, the second pressure sensor senses a second pressure of the first stream of air after compression in the first compressor, and the first temperature sensor senses a temperature of the first stream of air after compression in the first compressor. The controller adjusts a speed of the first compressor based upon a comparison between a desired flow rate and a calculated flow rate.

Abstract: A multi-fan apparatus and method incorporates mutual active cancellation of fan noise and/or vibrations. The multi-fan apparatus includes two or more fans circuits, each comprising a fan, a fan speed controller and a separate tachometer, and a fan phase controller. The phase controller is connected to at least one fan speed controller and to each tachometer. Each fan's speed is independently and dynamically maintained at the same set speed by the fan speed controllers using an independent control loops. A noise and/or vibration cancellation phase difference between fans is determined in order to achieve destructive interference of pressure waves and, thus, noise and/or vibration reduction, in pre-determined region of a system incorporating the multi-fan apparatus. The phase controller establishes and maintains this cancellation phase difference between the fans based upon feedback from the tachometers.

Abstract: A multi-stage compression system includes a plurality of centrifugal compression stages. Each stage includes an impeller and a variable speed motor coupled to the impeller. Each variable speed motor is operable at a speed between a first speed and a second speed. The multi-stage compression system also includes a control system that is connected to each of the variable speed motors and is operable to vary the speed of each motor. The speed of each motor is varied simultaneously such that a ratio of the speed of any two variable speed motors remains constant.

Abstract: The method of managing time M, at which maintenance of a gas compressor multiple system incorporating therein a plurality of gas compressors should be carried out, involves making a comparison between a value of M and a predetermined time N for necessary maintenance to carry out the maintenance when the value of M is larger than or substantially equal to a value of N, where M is equal to the product of the operating time T of the system, the average load factor L, and a safety factor C.

Abstract: A radiator blower, in particular for motor vehicles, is indicated that comprises a plurality of individual fans (11, 12), each having an electrical drive motor (13, 14), and a plurality of switches (S1, S2, S3), each capable of being switched over into two positions, by means of which the drive motors (13, 14) are capable of being turned on and back off individually or in a series or parallel connection. To prevent disturbing noises from developing when the individual fan (11, 12) comes to rest after being turned off, when the operating drive motor or motors (13, 14) is/are turned off, an electronic control unit (20) forces the switches (S1, S2, S3)—at least temporarily—over into switch positions that bring about a short-circuiting of the turned-off drive motor or motors (FIG. 1).

Abstract: A capacity control algorithm for a multiple compressor liquid chiller system is provided wherein the speed and number of compressors in operation are controlled in order to obtain a leaving liquid temperature setpoint. In response to an increase in the load in the chiller system, the algorithm determines if a compressor should be started and adjusts the operating speed of all operating compressors when an additional compressor is started. In response to a decrease in the load in the chiller system with multiple compressors operating, the algorithm determines if a compressor should be de-energized and adjusts the operating speed of all remaining operating compressors when a compressor is de-energized.

Abstract: A refrigerant supply apparatus for supplying a refrigerant to a cooling target. The apparatus includes a refrigerant supply channel through which pure water as the refrigerant is supplied to the cooling target, an impurity removing unit disposed in an impurity removing channel which is a channel different from the refrigerant supply channel, a sensor which measures a purity of the pure water, and a valve which stops supply of the pure water to the cooling target when the purity of the pure water does not satisfy a predetermined standard.

Abstract: This invention relates to a rotational speed control system including a plurality of motor drivers for driving motors, and the object thereof is to drive a plurality of motors at the same rotational speed without depending on the number of motor drivers and without depending on the characteristics of each motor driver. A remote controller 31 and a motor driver 202 are connected to a motor driver 201. The motor drivers 201 and 202 control motors M11 and M12 at a prescribed rotational speed, respectively. A rotational speed instructing signal 91 indicative of the rotational speed is supplied from the remote controller 31 to the motor driver 201, and further supplied from the motor driver 201 to the motor driver 202. Because the rotational speed instructing signal 91 indicates a rotational speed which is transmitted in a digital value between the motor drivers 201 and 202, both of the motors M11 and M12 are driven at the rotational speed indicated by the rotational speed instructing signal 91.

Abstract: A system and method are provided for variable speed operation of a screw compressor to obtain increased capacity and efficiency. The screw compressor is connected to an induction motor driven by a variable speed drive, wherein the screw compressor has a variable output capacity that is dependent on the output speed of the motor. To obtain increased capacity and efficiency, the screw compressor is operated at a speed greater than the screw compressor's rated speed and does not include a slide valve. The maximum operating speed of the screw compressor, which speed is greater than the rated speed, is related to the maximum operating speed of the motor when operated at a voltage and frequency provided by the variable speed drive that is greater than the motor's rated voltage and frequency in a constant flux or constant volts/Hz mode.

Abstract: A compressor assembly having a first compression mechanism operatively coupled to a first motor and a second compression mechanism operatively coupled to a second motor. The first compression mechanism compresses the vapor from a low pressure to an intermediate pressure and the second compression mechanism compresses the vapor from the intermediate pressure to a discharge pressure. An electrical circuit supplies electrical current to the first and second motors during operation of the compressor assembly. The electrical circuit includes means for, during start-up of the compressor assembly, initiating the supply of electrical current to the first motor at a first time and initiating the supply of electrical current to the second motor at a second time wherein the first time precedes the second time by a time lapse.

Abstract: A cooling fan including a fan module, a microcontroller, and a bus interface. The microcontroller is coupled to the fan module and is capable of adjusting a speed of the cooling fan based on a status of a second cooling fan and adjusting the speed of the cooling fan based on a temperature detected. The bus interface is in communication with the microcontroller, the second cooling fan, and the system to receive and output data.

Abstract: The present invention provides a fan installation for a cooling system of a motor vehicle, comprising at least two fans which respectively have an electric fan motor arranged in a separate housing and a fan wheel which can be driven by the fan motor. The fan installation also comprises a control unit for operating the fan motors. The invention provides for an improved fan installation with a simple and cost-effective design, which is achieved by arranging the control unit in the housing of one of the fans for operating both fan motors.

Abstract: The invention relates to a multistage compressor unit which comprises at least two different compressor elements (1 and 2) driven by means of separate electric motors (3, 4) with an adjustable speed, whereby the outlet (8) of a compressor element (1) of one stage connected to the inlet (10) of a successive compressor element (2) of a successive stage, characterized in that the electric motors (2, 4) are identical and therefore have approximately one and the same nominal capacity, whereas between each motor (3, 4) and the compressor element (1, 2) driven thereby, a gear transmission (13, 14) is provided.

Abstract: A multi-stage variable speed compressor includes a pressure detector provided for each compressor on and after the second stage for detecting a discharge pressure of a compressor of a stage preceding the corresponding compressor or a suction pressure of the corresponding compressor, wherein the control device controls the rotational speeds of the compressor of the first stage using a deviation of discharge pressure from a desired target pressure, and controls the rotational speed of each compressor on and after the second stage based on the discharge pressure of the compressor in a stage before each compressor or the suction pressure of each compressor, using a pressure signal from the pressure detector provided for each compressor on and after the second stage for detecting a discharge pressure of a compressor of a stage preceding the corresponding compressor or a suction pressure of the corresponding compressors.